1. Related Invention
The present invention is related to "An Improved Flaw Basket", Ser. No. 686,514, filed concurrently with this application by the same inventor.
2. Technical Field
The present invention relates to measuring flow rates in bore holes and, more particularly, to a method and apparatus for measuring the flow of fluids moving upwardly in a bore hole from an underlying oil and gas formation.
3. Background Art
It is important to ascertain the flow of fluids in bore holes from different underlying formations so that an indication as to the production of fluid, such as oil or gas, from each different formation can be determined. The present invention is adapted to measure fluid flow in multi-phase fluids in slanted or in vertical bore holes and prior to the application for the present invention, a patentability search was conducted. The results of the patentability search uncovered the following patents:
______________________________________ Inventor Reg. No. Issued ______________________________________ R. G. Piety 2,453,456 Nov. 9, 1948 Jean-Loup Bonnet Re. 28,464 July 8, 1975 Irvin D. Johnson 4,314,476 Feb. 9, 1982 ______________________________________
A discussion of conventional prior art devices for measuring fluid velocity of a well bore hole is set forth in U.S. Pat. No. 4,314,476 issued to the inventor on Feb. 9, 1982. The '476 patent relates to a restrictor which is inserted into the bore hole until it reaches a desired depth whereupon the restrictor is expanded. The expanded restrictor is pulled upwardly at a rate sufficient to maintain the differential pressure across the restrictor at zero thereby indicating that the rate that the restrictor is being pulled up is equal to the rate of fluid flow. The '476 invention relates to measurement of fluids that cause stirring action on the fluid velocity sensor.
The 1948 patent Piety (U.S. Pat. No. 2,453,456) relates to an instrument for measuring water flow in wells utilizing a series of vertically spaced geiger counters suspended in the well on a cable. Geiger counters are spaced at predetermined locations. A chamber containing radioactive material is initially positioned above the first geiger counter and then by means of a controlling electric current pulse, is caused to travel downwardly along the cable past each geiger counter. The rate that the chamber falls is controlled by the upward fluid movement of the water from the various formations. A disadvantage, with utilizing the Piety approach, is found in the handling of the radioactive materials which is disclosed primarily as being radon and the like.
The 1975 Bonnett patent is representative of the common "spinner" type flowmeter which utilizes spinners or turbines as the measurement device. Other spinner flowmeters are set forth in the "Background Art" sections of the '476 patent.